Power saving valve



Nov. 27, 1934.

J. G. MACLAREN POWER SAVING VALVE Filed Aug. i2, Vw51 Patented Nov. 27, 1934 UNITED STATES PATT oFFlCE N VPUVVER, SAVING VALVE y James G. Maclaren, San Francisco, Calif., asl signor to G & G Atlas Systems, Inc., New Yerk, N. Y., aI corporation of New York Application August 12,

7 Claims.

This invention is for use in pneumatic disso called by reason of. being arranged to permit.v

normally a small ow of air through the transit tube it controls and to increase this flowto carrier propelling force upon the dispatch of a l@ carrier.

' The main objects of this invention are to provide a valve which may be used either in tube systems of theV vacuum type, in which air is exhausted from in front of the carrier, the carrier 1.5-` being pushed along by atmospheric pressure; or Ain tube systems of the pressure type, in which air isy forced into theV transit` tube in back of the carrier at a pressure above the atmosphere- Also I have eliminated the need for valve opl erating pneumatics and the small by-passes andpilot valves used with these pneumatics, that my power saving valve may bel unaffected by damp or .dusty air.

My power saving valve can be4 operatively adiusted from the exterior and itsfunction-ing is easy to note. by observing the movements of exposed parts.

For a more complete descriptionof my invention refer to. the accompanying drawing,4 in Which: i e

Fig. 1 is a diagrammatic representation of a central station showing the location of the power saving valve in `a pneumatic tube system;

Fig. 2 is a front elevation of the power saving.

Y valve, with one section of the valve housing cu away along liney 2 2 in Fig. 3;

Fig. 3 is a side elevation of the valve, with a part of the valve housing broken lout to expose the interior, with parts in normal position when the` blower is in operation;

Fig. 4 is a vertical section along line 4-4 in Fig. 2 and shows the normal position of the partsy valv 193i, ksam-a1 No. 556,598 (ci. 24a-9) having a header 1 which is piped to a blower (not shown) arranged to maintain a substantiallyxed air pressure of varying volume in the header. V

This blower may be of the centrifugal type frequently used for this purpose. i

The header l has a series of air tube connec-V tions 2 each leading to a terminal 4 attached' to a transit tube This transit tube may loop through one or more sub-stations or may be arranged any manner required by the condi- .tions of any particular installation.

The terminal 4 is a common type suitable for 'either' a pressure or a vacuum system and has a vhinged and latched door `6. o

Inl a pressure system the air flow in the transit tube would be outward from the terminal 4 as indicated by the arrow 7. In a vacuum system the air would ilow toward vthe terminal 4 as indicated by the arrow 8. y 75 In a pressure system the terminal 4 would be usadas a sender, carriers to be dispatched being inserted into the tube 5 through the door 6.

In a vacuum system the terminal 4 would be a receiver of carriers discharged from the carrierpropelling airflow through the transit tube 5.

The power saving-valve 3 is connected into the air tube 2 with the air flowing through it in the direction indicated by the arrow 9 in Fig. 3.

The power saving valve consists of a casing 10 recessed at the ends 1l and 12 to t the air tubes 2 and contains a combined vane and valve, that -I call a van.evalve, to control the volume ofA air that'may pass through the transit tube 5.

The vane-valve is shown in Fig. 6 and consists -90 of a hinge piece 13 having secured to it -a plate 14 that rits over a port 15l in a partition 16 `that lseparates the interior of housing 10 into two chambers 17 and 18. Extra plates 19 and20 may beadded to increase the vane vsurfaceexposed to the kinetic energy of the carrier propelling air flow.

The vane-valve is shown closed over the port 15l in Fig. 4 and in anopen position in Fig. 7.

The face of the port 15 can be left unnished to permit the leakage of some air from chamber 17 to chamber 18. Such additional air as is required to maintain a suitable minimum flow of air through the transit tube 5, passes through. the I port 21 in the partition 16. The effectivearea of port 21 may be regulated by the screw plug. 22 that ilts a threaded hole 23 in the casing 10. The plug( 22 is locked in position by the locknut 24.

The minimum air flow is limited to an amount Y less than is required to create an air pressure sufilcient to move a carrier through the transit tube. Therefore there is a minimum air pressure on the face of the plate 14 toward the transit tube 5 when the vane-valve is closed and the transit tube 5 contains no carriers.

When a carrier (container in which things are transported) is placed in a transit tube it is, in ezeot, an obstruction that causes the air pressure back. of "he carrier to build up to a point that will move the carrier.

The air pressure above the plate 14 is greater than the mininum pressure referred to in the paragraph above, and less than the air pressure required to propel a carrier. I call it the intermediate pressure. It is nearer the pressure in the header than the pressure for the minimum air flow.

When. the vane-valve is open as illustrated in Fig. 7, the pressure in the header 1 becomes effective and the air flow in the transit tube becomes a maximum or carrier propelling air ow.

The vanenvalve shown in Fig. 6 is mounted in the housing l() on a square shaft that lits a square hole 26 in the binge piece 13. One end of 5 the shaft 25 is lathe turned to a round shape for asunicient distance to reach through the boss 27 and be secured by the pin 28. The other end or shaft 25 is supported in a round bearing 29 riding in a hole through the boss 30. The bosses f '27 and 30 are circular projections from the inner surface of the casing l0 and the distance between them ts the width of the hinge piece 13.

Outside of the housing 10 and bearing 29 on the shaft 25 is secured a casting having a lever arm 31 and a stop arm 32 that is arranged to engage terbaiance to open the vane-valve 13-14.

The strength of the motor spring pull may be adjusted by moving the nut 38 along the stem 39. The motor spring 40 constantly tends to open the vanevalve and the opening movement of the vane-valve on its shaft 25 is regulated and limited 7' by the engagement or" the stop arm 32 with the stop pin 33.

`The vane-valve opening effect of the motor spring 4o is regulated to be ineffective when a Y minimum iiow of air exists, but effective when Y the intermediate pressure on plate 14 exists by reason of the minimum flow being obstructed by a carrier.

The kinetic force due to the surge of the air column that takes place upon the discharge of a carrier, or its removal as an obstruction to the air dow, is suflicient to close the vane-valve to its sea-t over the port l5, where it is held by reason of the diierence between the pressure in the header 1 and the pressure on the opposite side of the closed air valve, which is suicient to overcome the normal opening effect of the counter* balance or motor spring 40.

The arrangement in Fig. 8 and Fig. 9 shows the substitution of a compound valve opening motor for the spring motor in Figs. 2 and 3.

The motor spring 40 and its associated parts are omitted. A beam 41 is attached to the square end of the shaft 25. At one end of the beam 41 is the balance weight 42 slidable on the beam 41 and secured in place by means of a set screw 43.

The beam 41 has a side projecting stop arm 44 and an extension 45 having a button 46 attached to its outer end and resting on, but not attached to the spring 47 which is attached to a recess in the projection 48 that is a part of the housing 10.

The spring 47 is compressed when the vanevalve is closed and its expanding movement is of limited length so that it operates as a part of the vane-valve opening motor only until the pressures on both sides of the plate 14 is balanced, or nearly so.

The stop pin 33 can be moved to locate the opened vane-Valve at a desirable position in the air Iiow and the balance weight 42 located at a point where it will hold the vane-valve open against the closing eiect of a carrier propelling air flow while it is obstructed by a carrier, but not against the flow existing when unobstructed, or surging by reason of a carrier being either discharged or delivered into a down fall section of transit tube.

It will be noted that when the blower is shut down the vane-valve will be releasedby the lack of air pressure and will open, and as the blowers used on systems equipped with power saving valves are usually of suiicient capacity to operate simultaneously only a limited number of the tubes or air circuits in the system, it is desirable to have a means to latch the vane-valve in the closed position when the blower is stopped. f

In the accompanying drawing I` have shown such a latching means in Figs. 2, 3, 4 and 7. Itis not always necessary to supply a latching means and thislatching means is omitted from the valve assembly shown in Figs. 8 kand 9.

The blowers used for tube systems are often of the centrifugal type and fitted with a quick opening and Aclosing blast gate. To reduce the starting load, the blast gate is closed while the driving motor is brought up to speed and then the blast gate is opened. This quick opening will, on many systems, surge the air through all the tubes in the system suiiiciently to close the vane-valves andthe momentary overload on the blower will do no damage. However, to meet market requirements completely, it should be possible to arrange the valve sov that it may be closed when the blower isfnot operating.

For a valve latching means,` the vane-valve hinge piece 13 has a catch 49 so arranged that under conditions to bev described, the catch will be engaged by the bolt 50 to hold the vane-valve in its closed, or nearly closed position, over port 15.

The casing 10 has an opening 51 covered by a flexible diaphragm 52. The diaphragm 52 is clamped in place under the ring 53 and on this ring are ears 54 and 55 through which passes a pin 56 to serve as a fixed pivot for a rocker bar 57.

The rocker bar 57 is hinged to a stud 58 by the pin 59. The rocker bar 57 has two elongated holes 60 and 61, either oneof which may be used for hinging the rocker bar 57 to the bolt 50 by means of the pin 62. There is a slot in the ends of bolt 50 and stud 58, also between the ears 54 andv55, to receive the rocker bar 57.

The bo1t50 is movably supported in the hole 63 through the casing 10 and hole 64 Athrough the partition 16. The stud 58 is shouldered forthe washers 69 and 70, and to pass through the diaphragm 52 and threaded for the nut 71 to clamp the stud 58 to the diaphragm 52.

One side of the diaphragm 52 is exposed to atmospheric pressure and the other to the air pressure existing in the chamber 18.

Used in a pressure tube system, the air pressure in chamber 18 would tend to blow the diaphragm 52, and stud 58, outward until movement is stopped by reason of the washer making up against the inner face of the opening 51 as shown* in Fig. 7.

In a vacuum tube system the stud 58 and diaphragm 52 would be moved inwardly until stopped by the nut '7l striking the partition 16.'

For use in a vacuum system, thevroclrer` bar 57 is pinned to the bolt 50 through the hole 61, and the ears 54 and 55 are located as shown in Figs. 2, 3 and 4.

For use in a pressure system, the ring 53 is mounted to locate the ears 54 and 55 as indicated by the dotted lines 54a and 55a in Fig. 2 and as shown in Fig. '7.

The air pressure on the diaphragm 52 always tends to rotate the rocker arm about its pivot on pin 56 to push the bolt outward and clear of the catch 49.

Tending to push the bolt inward under theY catch 49 is a spring 66 having one end 65 secured to the casing 10 by the screw 68. The free end v6'? of the spring 66 is bent to rest on the bottom of the slot in the end of bolt 50 as indicated in the drawing.

The spring 66 tends to push the bolt 50 inward, but its effective force is less than that of the air pressure on the diaphragm 52.

When the blower is to be stopped and as it begins to lose speed, the air pressure in the chainber 18 will change with the speed of the blower, and the spring 66 having been adjusted to overcome the force of the diaphragm at an air pressure that will exist when the blower first begins to lose speed, the spring 66 can push the bolt 50 under the catch 49, before the motor spring 40 can function, thereby preventing the wide opening of the vane-valve from over the port 15.

The operation of this power saving valve is substantially as follows, it being assumed that when the blower is in operation, the Valve parts will occupy the positions shown in Figs. 2, 3 and 4, and air is being exhausted from the transit tube 5 through the terminal 4, valve 3, air tube 2 and header 1 to the blower used to do this work:

A minimum amount of air will be flowing, with correspondingly weak air pressure, in the transit tube 5.

A carrier having been placed in the transit tube, say for transmission from a sub station (not shown) to the central station terminal 4,

, will be an obstruction or stopper to lessen the volume of the air flow to what may escape past the carrier. This will increase the partial vacuum between the carrier and the plate 14 until the atmospheric pressure on the carrier starts the carrier in motion.

The motor spring 40 will have been adjusted to open the vane-valve (i3-14) when the suction on the plate 14 has been reduced to the intermediate pressure by the increased partial vacuum, or air pressure drop, on the transit tube side of the plate 14.

The motor spring 40 having functioned to open the vane-valve, a carrier propelling air ilow will have been established in the transit tube 5.

Upon the discharge of the carrier into the terminal 4, the air column will surge forward as soon as the load (the carrier) is released and the impact of this air column on the plate 14 (or plates 14, 19 and 20) leaning into the air flow as indicated in Fig. r'7, will overcome the valve to Lthe closed position indicated in Figs. 3 and 4 where vit will be held by the suction in chamber 18;

The further the plate l4leans toward its closed position, the more effective will be the force of the air surge, and by means of the adjustable stop 33 the plate 14 (now acting as a vane) can be located inthe open position where it is most responsivevto the air surge that follows the release of a carrier.

It will be understood that while a carrier is at rest the velocity of the air past the vane-valve, while it is opening, lis very low and adds very little resistance tothe opening force of the motor spring 40. Y

The operation of avalve for a pressure system is similar to the above, the difference being that the blower `operates as a compressor and the minimum, intermediate and carrier propelling air pressures are above that of the atmosphere.

The operation and use of the valve latching means was described above. Also, the omission of the valve latching means and substitution of an alternate valve opening motor as shown in Figs. 8 and 9 were explained above.

It is to be understood that while preferred embodiments of thisl invention have been shown herein by way of example, various changes in the proportionsand,arrangements of parts may be made if desired and that equivalent parts may be substituted for those shown and described herein andthat some parts may be omitted without departing from the invention.

In the following claims the words pneumatic tube system mean the combination of a transit tube, means for creating a carrier 'propelling air flow and means for the insertion of a carrier into the transit tube and dischargingit at its destination. Many types of the various parts are available.

A dual flow type of pneumatic tube system is to be understood as one in which a minimum or limited iiow of air is normally maintained through the transit tube and a carrier propelling air flow maintained during the flight of a carrier.

I claim: 1. Po-wer saving apparatus for a pneumatic tension of the motor spring 40 and snap thevane` l. littl tube system of the dual ow type, said apparatus comprising a normally closed valve having multiple vane surfaces in fixed, spaced relation and a motor having potential energy stored therein for opening the valve in response to a changed air pressure in the transit tube due to the dispatch of a carrier.

2. Power saving apparatus for a pneumatic tube system of the dual flow type, said apparatus comprising a normally closed multivane valve having the vane surfaces in fixed, spaced relation, a motor having potential energy stored therein fo-r opening the valve in response to a changed air pressure in the transit tube due to the dispatch of a carrier, the said valve being closed by the kinetic action of the air upon the spaced vanes when the carrier is delivered.

3. In a pneumaticy tube system, a vane-valve controlling the flow of air, a latch directly responsive to the pressure on the low pressure side of the valve for retaining said valve in closed position, a motor to open the valve, said motor exerting maximum force at the moment of opening the valve and applying a lesser force to hold said valve open until the valve is closed by the surge of air that follows a carrier delivery.

4. In a pneumatic tube system of the dual ow type, a valve controlling the ow of air through the transit tube, a latch directly responsive to the pressure on the low pressure side of the Valve for retaining said valve in closed position, and a valve opening motor functioning by reason of variations in air force directly applied to said valve.

5. In a pneumatic tube system of the dual flow type, a normally closed valve controlling the flow of air through the transit tube, a latch directly responsive to the pressure on the low pressure side of the valve for retaining said Valve in closed position, and Valve opening means attached to the valve and constantly applying a force tending to open the valve, but inoperative while the transit tube is unobstructed.

6. In a pneumatic tube system a tube, a valve casing, power means connected with saidI casing' for changing the air pressure Within said tube, a valve within said casing for controlling the ow of air through said tube, and a latch directly responsive to the pressure on the low pressure side of said valve for holding the same closed.

7. In a pneumatic tube system'a tube, a valve casing, power means connected with said casing for changing the air pressure within said tube, a valve within said casing for controlling the flow of air through said tube, and means directly responsive to the pressure on the low pressure side of said Valve for preventing opening of said valve when said power means is below normal operation.

JAMES G. MACLAREN. 

